(a) Field of the Invention The present disclosure relates to a liquid crystal display (LCD).
(b) Discussion of the Related Art
An LCD is one of the most widely used flat panel displays. An LCD includes two display panels provided with electric field generating electrodes, such as pixel electrodes and a common electrode, and a liquid crystal layer interposed between the two display panels. In the LCD, voltages are applied to the electric field generating electrodes to generate an electric field in the liquid crystal layer. Due to the generated electric field, liquid crystal molecules of the liquid crystal layer are aligned and polarization of incident light is controlled, thereby displaying images.
The liquid crystal displays also include switching elements connected to individual pixel electrodes, and a plurality of signal lines, such as gate lines and data lines, for controlling the switching elements so as to apply voltages to the pixel electrodes.
Among the LCDs, a vertical alignment (VA) mode LCD, which aligns LC molecules such that their long axes are perpendicular to the panels in the absence of an electric field, is spotlighted because of its high contrast ratio and wide reference viewing angle. Here, the reference viewing angle can be a viewing angle that has a contrast ratio of 1:10, or a critical angle of gray-to-gray luminance reversion.
To approximate side visibility to front visibility in the vertical alignment mode LCD, a method of causing a difference in transmittance by dividing one pixel into two sub-pixels and applying different voltages to the two sub-pixels has been suggested.
An example of the method includes applying the same voltage to two sub-pixels and dropping the voltage of one sub-pixel by using a separate switching element. In the LCD, when the polarity of the pixel voltage is reversed, due to the difference between the pixel voltage charged during the previous frame and the pixel voltage charged during the present frame, the capacitance of a step-down capacitor may be changed, and it becomes difficult to correctly control the voltages of two sub-pixel electrodes.
Therefore, when the voltages of two sub-pixel electrodes are not correctly controlled and the voltage charged during the previous frame is influenced, display quality is deteriorated.